(IUCr) Redetermination of the borax structure from laboratory X-ray data at 145 K

Volume 64
Part 5
Pages i24-i25
May 2008

Received 26 March 2008
Accepted 15 April 2008
Online 23 April 2008

Key indicators
Single-crystal X-ray study
T = 145 K
Mean (O-B) = 0.001 Å
R = 0.025
wR = 0.077
Data-to-parameter ratio = 15.5
Details

Redetermination of the borax structure from laboratory X-ray data at 145 K

Graeme J. Gainsford,^a ^* Tim Kemmitt ^a and Caleb Higham ^a

^aIndustrial Research Limited, PO Box 31-310, Lower Hutt, New Zealand
Correspondence e-mail: g.gainsford@irl.cri.nz

The title compound, sodium tetraborate decahydrate (mineral name: borax), Na₂[B₄O₅(OH)₄]·8H₂O, has been studied previously using X-ray [Morimoto (1956). Miner. J. 2, 1-18] and neutron [Levy & Lisensky (1978). Acta Cryst. B34, 3502-3510] diffraction data. The structure contains tetraborate anions [B₄O₅(OH)₄]^2- with twofold rotation symmetry, which form hydrogen-bonded chains, and [Na(H₂O)₆] octahedra that form zigzag chains [Na(H₂O)_4/2(H₂O)_2/1]. The O-H bond distances obtained from the present redetermination at 145 K are shorter than those in the neutron study by an average of 0.127 (19) Å.

Related literature

For previous studies of the borax structure, see: Morimoto (1956); Levy & Lisenky (1978). For other structures listed in the Cambridge Structural Database (Allen, 2002) that contain the [B₄O₅(OH)₄]^2- anion, see: Wang et al. (2004); Pan et al. (2007). For related structures, see: Yi et al. (2005). For comparative studies of hydrogen bonds obtained from X-ray and neutron data, see: Allen (1986); Smrcok et al. (2006).

Experimental

Crystal data

Na₂[B₄O₅(OH)₄]·8H₂O
M_r = 381.38
Monoclinic, C 2/c
a = 11.8843 (5) Å
b = 10.6026 (4) Å
c = 12.2111 (5) Å
= 106.790 (2)°
V = 1473.06 (10) Å³
Z = 4
Mo K radiation
= 0.22 mm^-1
T = 145 (2) K
0.65 × 0.36 × 0.26 mm

Data collection

Bruker-Nonius APEX2 CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2006) T_min = 0.813, T_max = 0.94
8429 measured reflections
2275 independent reflections
2137 reflections with I > 2(I)
R_int = 0.018

Refinement

R[F² > 2(F²)] = 0.025
wR(F²) = 0.076
S = 1.08
2275 reflections
147 parameters
All H-atom parameters refined
_max = 0.37 e Å^-3
_min = -0.22 e Å^-3

Table 1
Selected bond lengths (Å)

Na1-O8ⁱ	2.3815 (6)
Na1-O6ⁱⁱ	2.3979 (5)
Na1-O7	2.4121 (6)
Na2-O7ⁱⁱⁱ	2.4041 (6)
Na2-O9	2.4214 (6)
Na2-O6	2.4441 (6)
B1-O4	1.4451 (8)
B1-O1	1.4657 (7)
B1-O2	1.4902 (8)
B1-O3	1.5075 (8)
B2-O2	1.3655 (8)
B2-O3ⁱ	1.3757 (8)
B2-O5	1.3784 (8)
Symmetry codes: (i) $[-x, y, -z+{\script{1\over 2}}]$ ; (ii) $[-x, y-1, -z+{\script{1\over 2}}]$ ; (iii) $[-x, y+1, -z+{\script{1\over 2}}]$ .

Table 2
Hydrogen-bond geometry (Å, °)

D-HA	D-H	HA	DA	D-HA
O5-H5^ivO3^iv	0.836 (15)	1.895 (15)	2.7300 (7)	176.3 (15)
O4^v-H4O9^vi	0.828 (14)	2.049 (14)	2.8658 (8)	168.4 (12)
O6-H6A^viiO5^viii	0.868 (16)	1.978 (16)	2.8323 (8)	167.9 (14)
O6^ix-H6BO4^v	0.846 (16)	2.040 (15)	2.8624 (8)	163.9 (16)
O7^vii-H7AO2	0.827 (16)	1.989 (16)	2.8135 (8)	174.1 (12)
O7-H7BO4	0.816 (15)	2.135 (15)	2.9233 (8)	162.3 (14)
O8^v-H8AO1^x	0.866 (13)	1.936 (13)	2.7865 (6)	167.0 (14)
O8^v-H8BO5^xi	0.855 (15)	2.341 (14)	3.1320 (8)	154.2 (12)
O9-H9A^viiO3	0.843 (16)	2.253 (16)	3.0894 (8)	171.7 (15)
O9-H9B^xiiO8^xiii	0.849 (17)	2.069 (16)	2.9034 (8)	167.4 (15)
Symmetry codes: (iv) $[x, -y+1, z+{\script{1\over 2}}]$ ; (v) $[-x+1, y, -z+{\script{1\over 2}}]$ ; (vi) $[x+{\script{1\over 2}}, y-{\script{1\over 2}}, z]$ ; (vii) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (viii) $[-x+{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1]$ ; (ix) -x+1, -y+1, -z+1; (x) x+1, y, z; (xi) $[x+{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (xii) $[x-{\script{1\over 2}}, y+{\script{1\over 2}}, z]$ ; (xiii) $[x, -y+1, z-{\script{1\over 2}}]$ .

Data collection: APEX2 (Bruker, 2006); cell refinement: APEX2; data reduction: APEX2; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: WM2174 ).

Acknowledgements

We thank Dr J. Wikaira of the University of Canterbury, New Zealand, for her assistance with the data collection.

References

Allen, F. H. (1986). Acta Cryst. B42, 515-522.
Allen, F. H. (2002). Acta Cryst. B58, 380-388.
Bruker (2006). APEX2 and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.
Levy, H. A. & Lisensky, G. C. (1978). Acta Cryst. B34, 3502-3510.
Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453-457.
Morimoto, N. (1956). Miner. J. 2, 1-18.
Pan, C.-Y., Wang, G.-M., Zheng, S.-T. & Yang, G.-Y. (2007). Acta Cryst. E63, o1207-o1209.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.
Smrcok, L., Sládkovicová, M., Langer, V., Wilson, C. C. & Koós, M. (2006). Acta Cryst. B62, 912-918.
Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.
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Yi, X.-Y., Liu, B., Jimenez-Aparicio, R., Urbanos, F. A., Gao, S., Xu, W., Chen, J.-S., Song, Y. & Zheng, L.-M. (2005). Inorg. Chem. 44, 4309-4314.

inorganic compounds